Sample processing units, systems, and related methods

ABSTRACT

Sample processing units useful for mixing and purifying materials, such as fluidic materials are provided. A sample processing unit typically includes a container configured to contain a sample comprising magnetically responsive particles, and one or more magnets that are in substantially fixed positions relative to the container. A sample processing unit also generally includes a conveyance mechanism configured to convey the container to and from a position that is within magnetic communication with the magnet, e.g., such that magnetically responsive particles with captured analytes can be retained within the container when other materials are added to and/or removed from the container. Further, a sample processing unit also typically includes a rotational mechanism that is configured to rotate the container, e.g., to effect mixing of sample materials disposed within the container. Related carrier mechanisms, sample processing stations, systems, and methods are also provided.

The present application is a continuation of U.S. patent application Ser. No. 13/595,189 filed Aug. 27, 2012, now U.S. Pat. No. 8,609,430, issued Dec. 17, 2013, which is a continuation of U.S. patent application Ser. No. 13/221,608 filed Aug. 30, 2011, now U.S. Pat. No. 8,252,599, issued Aug. 28, 2012, which is a continuation of U.S. patent application Ser. No. 12/561,175 filed Sep. 16, 2009, now U.S. Pat. No. 8,148,163, issued Apr. 3, 2012, which claims priority to U.S. Provisional Application Ser. No. 61/097,525 filed Sep. 16, 2008, each of which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to sample purification, and provides sample processing units, systems, and methods useful for this purpose.

BACKGROUND OF THE INVENTION

Nucleic acid amplification techniques, such as the polymerase chain reaction (PCR) have widespread applications in many scientific disciplines, including microbiology, medical research, forensic analysis, and clinical diagnostics. In some of these applications, PCR products are “sized” using traditional biochemical techniques such as standard gel electrophoresis involving either intercalating dyes or fluorescently labeled primers. Other applications, such as 5′-nuclease or TaqMan® probe-based assays, which are widely used in a number of PCR-related diagnostic kits, confirm the presence (or absence) of a specific PCR product, but provide no direct information on the size of the particular amplicon. These methods typically have limited utility for relatively small amplicons (less than 150 base pairs), owing to the proportionately high fluorescence background, and do not provide any information with respect to amplicon heterogeneity or exact length.

Electrospray ionization mass spectrometry (ESI-MS) has become an important technique for the analysis of biopolymers, including nucleic acids. Compared to the more traditional nucleic acid analysis methods mentioned above, ESI-MS as a platform on which to characterize PCR products typically provides improved speed, sensitivity, and mass accuracy, among other attributes. Further, since the exact mass of each nucleotide or nucleobase is known with great accuracy, a high-precision mass measurement obtained via mass spectrometry can be used to derive a base composition within the experimentally obtained mass measurement uncertainty. In certain applications, the base compositions of PCR products are used to identify unknown bioagents, genotype nucleic acids, and provide drug resistance profiles as well as other information about the corresponding template nucleic acids or source organisms.

In the electrospray ionization process, large charged droplets are produced in the process of “pneumatic nebulization” where the analyte solution is forced through a needle at the end of which is applied a potential sufficient to disperse the emerging solution into a very fine spray of charged droplets all of which have the same polarity. The solvent evaporates, shrinking the droplet size and increasing the charge concentration at the droplet's surface. Eventually, at the Rayleigh limit, Coulombic repulsion overcomes the droplet's surface tension and the droplet explodes. This “Coulombic explosion” forms a series of smaller, lower charged droplets. The process of shrinking followed by explosion is repeated until individually charged analyte ions are formed. The charges are statistically distributed amongst the analyte's available charge sites, leading to the possible formation of multiply charged ions. Increasing the rate of solvent evaporation, by introducing a drying gas flow counter current to the sprayed ions, increases the extent of multiple-charging. Decreasing the capillary diameter and lowering the analyte solution flow rate, e.g., in nanospray ionization, typically creates ions with higher mass-to-charge (m/z) ratios (i.e., it is a softer ionization technique) than those produced by “conventional” ESI and are commonly used in the field of bioanalysis.

ESI generally requires relatively clean samples and is intolerable of cationic salts, detergents, and many buffering agents commonly used in biochemical laboratories. Buffer systems commonly employed in polymerase chain reactions, for example, typically include electrospray incompatible reagents such as KCl, MgCl₂, Tris-HCl, and each of the four deoxynucleotide triphosphates (dNTPs). Even the presence of relatively low concentrations of metal cations (e.g., less than 100 μM) can reduce MS sensitivity for oligonucleotides as the signal for each molecular ion is spread out over multiple salt adducts. Thus, in addition to removing detergents and dNTPs, effective ESI-MS of PCR products typically requires that the salt concentration be reduced by more than a factor of 1000 prior to analysis.

Ethanol precipitation has been used to desalt PCR products for subsequent MS analysis as short oligonucleotides and salts are removed while the sample is concentrated. In some of these methods, the PCR product can be precipitated from concentrated ammonium acetate solutions, either overnight at 5° C. or over the course of 10-15 minutes with cold (−20° C.) ethanol. Unfortunately, a precipitation step alone is generally insufficient to obtain PCR products which are adequately desalted to obtain high-quality ESI spectra; consequently, precipitation is generally followed by a dialysis step to further desalt the sample. While several approaches have successfully employed these methods to characterize a number of PCR products, there remains a need to apply these and related methods in a robust and fully automated high-throughput manner.

SUMMARY OF THE INVENTION

The present invention provides sample processing units that are useful in various purification processes. In certain embodiments, for example, the sample processing units are used to perform solution capture methods of purifying nucleic acids, which are subsequently analyzed using any suitable approach, including electrospray mass spectrometric-based analysis. Some of these embodiments include adding an anion exchange resin to the solution and mixing these materials in a sample processing unit to yield a suspension of the anion exchange resin in the solution in which the nucleic acids bind to the anion exchange resin. Additional processing steps performed using the sample processing units described herein typically include isolating the anion exchange resin from the solution, washing the anion exchange resin to remove one or more contaminants with one or more wash buffers while retaining the nucleic acids bound to the resin, and eluting the nucleic acids from the anion exchange resin with an elution buffer, thereby yielding purified nucleic acids that are suitable for further analysis. In addition to sample processing units and stations, the invention also provides related systems and methods.

In one aspect, the invention provides a sample processing unit that includes at least one container (e.g., a cuvette or the like) configured to contain at least one sample comprising at least one magnetically responsive particle (e.g., a magnetically responsive bead coated with a selected capture reagent, etc.), and at least one magnet (e.g., a permanent magnet, an electromagnet, etc.) that generates, or is configured to generate, at least one magnetic field, which magnet is in a substantially fixed position relative to the container. The sample processing unit also includes at least one conveyance mechanism configured to convey the container between at least first and second positions in which at least the first position is within magnetic communication with the magnet when the magnet generates the magnetic field, and at least one rotational mechanism operably connected to the container, which rotational mechanism is configured to rotate the container when the container is in at least the second position. Typically, the sample processing unit includes at least one mounting bracket that is operably connected to one or more of: the container, the magnet, the conveyance mechanism, or the rotational mechanism. In some embodiments, a sample processing station includes the sample processing unit. In certain embodiments, a carrier mechanism includes the sample processing unit. In some of these embodiments, a system includes the carrier mechanism.

In some embodiments, the conveyance mechanism comprises at least one motor. The conveyance mechanism is configured to rotate the container between the first and second positions in certain embodiments. In other exemplary embodiments, the conveyance mechanism is configured to slide the container between the first and second positions. To further illustrate, in some embodiments, the conveyance mechanism comprises at least one support member operably connected to the container and/or to the rotational mechanism. In some of these embodiments, the support member is configured to slide between the first and second positions, whereas in other exemplary embodiments, the support member is configured to rotate between the first and second positions.

In certain embodiments, the rotational mechanism is configured to rotate the container in at least one pulsed mode, during which a substantial portion of the time of rotation, a rate of rotation of the container exceeds a rate of rotation of the sample when the container contains the sample such that the sample is sheared away from a surface of the container. In some embodiments, the rotational mechanism is configured to rotate the container in at least one oscillating motion.

In another aspect, the invention provides a sample processing unit that includes at least one cuvette configured to contain at least one sample comprising at least one magnetically responsive particle, and at least one magnet (e.g., a permanent magnet, an electromagnet, etc.) that generates, or is configured to generate, at least one magnetic field, which magnet is in a substantially fixed position. In some embodiments, two or more magnets are disposed proximal to a receiving space in which the cuvette is located at least partially within the receiving space when the cuvette is in the first position. The sample processing unit also includes at least a first motor operably connected to the cuvette. The first motor is configured to rotate the cuvette around a central longitudinal axis of the cuvette. In addition, the sample processing unit also includes at least one support member (e.g., a swing arm or the like) operably connected to the first motor, and at least a second motor operably connected to the support member. The second motor is configured to rotate the cuvette between at least first and second positions in which at least the first position is within magnetic communication with the magnet when the magnet generates the magnetic field. In certain embodiments, a sample processing station includes the sample processing unit. Optionally, a carrier mechanism (e.g., a carousel, a conveyor track, etc.) includes the sample processing unit. In some of these embodiments, a system includes the carrier mechanism.

In some embodiments, the first motor (e.g., a stepper motor, a servo motor, etc.) is configured to rotate the cuvette in at least one pulsed mode, during which a substantial portion of the time of rotation, a rate of rotation of the cuvette exceeds a rate of rotation of the sample when the cuvette contains the sample such that the sample is sheared away from a surface of the cuvette, e.g., to effect thorough mixing of the sample and other materials that may be present in the cuvette. To further illustrate, the first motor is optionally configured to rotate the cuvette in at least one oscillating motion. In certain embodiments, the second motor comprises a brushless direct current motor or the like. The sample processing unit generally includes circuitry configured to control the first and second motors.

In certain embodiments, the support member comprises a first end and a second end in which the cuvette is retained at or proximal to the first end of the support member, and in which the second motor is operably connected to the support member at or proximal to the second end of the support member. In some of these embodiments, the support member is configured to rotate at least partially around a rotational axis extending through the second end of the support member. As a further illustrate, in some embodiments, a pin is fixedly coupled to the second end of the support member and aligned with the rotational axis in which the pin is operably coupled to the second motor.

In some embodiments, the sample processing unit includes a mounting bracket in which the support member is operably connected to the mounting bracket. In certain of these embodiments, the magnet is operably connected to the mounting bracket.

In another aspect, the invention provides a sample processing system. The system includes at least one sample processing unit that comprises: at least one cuvette configured to contain at least one sample comprising at least one magnetically responsive particle; at least one magnet that generates, or is configured to generate, at least one magnetic field, which magnet is in a substantially fixed position; at least a first motor operably connected to the cuvette, which first motor is configured to rotate the cuvette around a central longitudinal axis of the cuvette; at least one support member operably connected to the first motor; and at least a second motor operably connected to the support member, which second motor is configured to rotate the cuvette between at least first and second positions in which at least the first position is within magnetic communication with the magnet when the magnet generates the magnetic field. The system also includes at least one carrier mechanism operably connected to the sample processing unit. The carrier mechanism is configured to move the sample processing unit to one or more locations. The system further includes at least one material transfer component configured to transfer material to and/or from the cuvette, and at least one controller operably connected to the sample processing unit, the carrier mechanism, and/or the material transfer component. The controller is configured to effect one or more of: the magnet to generate the magnetic field, the first motor to rotate the cuvette, the second motor to rotate the cuvette between the first and second positions, the carrier mechanism to move the sample processing unit to the one or more locations, or the material transfer component to transfer the material to and/or from the cuvette.

The carrier mechanism includes various embodiments. In one embodiment, for example, the carrier mechanism comprises a carousel that is configured to rotate the sample processing unit to the one or more locations. In another exemplary embodiment, the carrier mechanism comprises a conveyor track that is configured to convey the sample processing unit to the one or more locations. Typically, the carrier mechanism comprises a plurality of sample processing units. In some of these embodiments, the material transfer component comprises a manifold that is configured to transfer material to and/or from the cuvettes of at least two sample processing units substantially simultaneously.

In some embodiments, the material transfer component comprises one or more of: a sample input gantry head, a sample wash station, a sample output gantry head, or a cuvette wash station. Typically, the material transfer component is configured to transfer fluidic material. In certain embodiments, the material transfer component comprises one or more needles.

In certain embodiments, the controller is configured to effect the first motor to rotate the cuvette in one or more selectable modes. In some embodiments, for example, the controller is configured to effect the first motor to rotate the cuvette in at least one pulsed mode, during which a substantial portion of the time of rotation, a rate of rotation of the cuvette exceeds a rate of rotation of the sample when the cuvette contains the sample such that the sample is sheared away from a surface of the cuvette. In other exemplary embodiment, the controller is configured to effect the first motor to rotate the cuvette in at least one oscillating motion.

In some embodiments, the sample processing system includes at least one detector configured to detect one or more detectable signals of or from one or more sample components. In certain embodiments, the detector is within sensory communication with the cuvette when the carrier mechanism moves the sample processing unit to at least one of the locations. Optionally, the material transfer component is configured to transfer the material from the cuvette to the detector. In some embodiments, the controller is operably connected to the detector. In these embodiments, the controller is configured to effect the detector to detect the detectable signals of or from the sample components. To further illustrate, in certain embodiments, the detector comprises a mass spectrometer. In some of these embodiments, the mass spectrometer comprises an electrospray ionization time-of-flight mass spectrometer.

In another aspect, the invention relates to a method of processing a sample. The method includes (a) providing at least one sample processing unit that comprises: at least one cuvette that contains at least one sample comprising at least one magnetically responsive particle comprising at least one captured first component (e.g., a biopolymer, such as a polynucleotide, a polypeptide, or the like); at least one magnet that is in a substantially fixed position; at least a first motor operably connected to the cuvette, which first motor is configured to rotate the cuvette around a central longitudinal axis of the cuvette; at least one support member operably connected to the first motor; and at least a second motor operably connected to the support member, which second motor is configured to rotate the cuvette between at least first and second positions in which the magnet is capable of magnetically communicating with the cuvette when the cuvette is at least in the first position. The method also includes (b) moving the cuvette into the first position using the second motor such that a magnetic field generated by the magnet causes the magnetically responsive particle to move and/or be retained proximal to a surface of the cuvette. In addition, the method also includes (c) removing at least a second component from the cuvette to thereby process the sample. In some embodiments, the method includes adding the sample and/or the magnetically responsive particle to the cuvette prior to (a) when the cuvette is in the second position. Optionally, the method includes adding at least one wash reagent to the cuvette. In certain embodiments, the magnet comprises a permanent magnet. In other exemplary embodiments, the magnet comprises an electromagnet. In these embodiments, the method typically comprises generating the magnetic field prior to or during (b). Typically, a carrier mechanism comprises the sample processing unit and the method comprises moving the sample processing unit to one or more locations.

The magnetically responsive particle includes various embodiments. In some embodiments, for example, the magnetically responsive particle comprises an anion exchange resin. Typically, the magnetically responsive particle comprises at least one biopolymer capture reagent. In certain embodiments, the biopolymer capture reagent comprises at least one anion exchange functional group. The anion exchange functional group typically comprises a pKa value of 9.0 or greater. To further illustrate, exemplary anion exchange functional groups are selected from, e.g., a primary amine, a second amine, a tertiary amine, a quaternary amine, a polyethyleneimine, a charged aromatic amine, a diethylaminomethyl, a diethylaminoethyl.

The method typically includes rotating the cuvette using the first motor such that sample components mix with one another. In some embodiments, the method includes rotating the cuvette when the cuvette is in the second position. In certain embodiments, the method includes rotating the cuvette in at least one pulsed mode, during which a substantial portion of the time of rotation, a rate of rotation of the cuvette exceeds a rate of rotation of the sample such that the sample is sheared away from a surface of the cuvette. Optionally, the method includes rotating the cuvette in at least one oscillating motion.

In certain embodiments, the method includes detecting at least one detectable signal of or from the sample. For example, the method optionally includes detecting a molecular mass of the first component. In these embodiments, the molecular mass is generally detected using a mass spectrometer. In some of these embodiments, the first component comprises a nucleic acid and the method comprises correlating the molecular mass of the nucleic acid with a base composition and/or an identity of the nucleic acid.

BRIEF DESCRIPTION OF THE DRAWINGS

The description provided herein is better understood when read in conjunction with the accompanying drawings which are included by way of example and not by way of limitation. It will be understood that like reference numerals identify like components throughout the drawings, unless the context indicates otherwise. It will also be understood that some or all of the figures may be schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.

FIG. 1A schematically shows a sample processing unit with a cuvette in a second position from a perspective view according to one embodiment of the invention.

FIG. 1B schematically depicts the sample processing unit of FIG. 1A with the cuvette in a first position from a perspective view.

FIG. 1C schematically depicts the sample processing unit of FIG. 1A with the cuvette in a first position from a side elevation view.

FIG. 1D schematically illustrates a detailed side elevation view of a motor operably connected to a cuvette of the sample processing unit of FIG. 1A.

FIG. 2 is a mass spectrum obtained for a 65-mer PCR product following a purification and desalting protocol described herein. The two peaks correspond to sense and antisense strands of the PCR amplicons, which separate under the conditions of ESI. Low amplitude salt adducts indicated effective cleanup of the PCR product.

FIG. 3A schematically shows a sample processing unit with a slidable support member in a first position from a front elevation view according to one embodiment of the invention.

FIG. 3B schematically depicts the sample processing unit of FIG. with the slidable support member in a second position from a perspective view.

FIG. 4A schematically illustrates a carrier mechanism with a manifold from a perspective view according to one embodiment of the invention.

FIG. 4B schematically shows the carrier mechanism and manifold of FIG. 4A from a side elevation view.

FIG. 4C schematically shows the carrier mechanism and manifold of FIG. 4A from a top view.

FIG. 4D schematically illustrates a detailed perspective view of the carrier mechanism and manifold of FIG. 4A.

FIG. 4E schematically depicts a detailed side elevation view of the carrier mechanism and manifold of FIG. 4A.

FIG. 4F schematically depicts a detailed front elevation view of the carrier mechanism and manifold of FIG. 4A.

FIG. 5A schematically illustrates a carrier mechanism that includes a conveyor track from a top view according to one embodiment of the invention.

FIG. 5B schematically illustrates the carrier mechanism from FIG. 5A from a side elevation view.

FIG. 6 is a block diagram showing a representative logic device in which various aspects of the present invention may be embodied.

FIG. 7A schematically illustrates selected components of a representative system that includes a sample processing station as a sub-system component from a perspective view according to one embodiment of the invention.

FIG. 7B schematically shows the representative system of FIG. 7A from a front elevation view.

FIG. 7C schematically depicts the representative system of FIG. 7A from a rear elevation view.

FIG. 7D schematically shows the representative system of FIG. 7A from a side elevation view.

FIG. 7E schematically illustrates the representative system of FIG. 7A from a top elevation view.

FIG. 7F schematically depicts the representative system of FIG. 7A from a cross-sectional view.

FIG. 7G schematically illustrates the representative system of FIG. 7A from a cross-sectional view.

FIG. 8A and FIG. 8B schematically show additional components of a representative system of FIG. 7A from a perspective view.

FIG. 9A schematically illustrates the representative system of FIG. 7A with an external covering from a perspective view.

FIG. 9B schematically illustrates the representative system of FIG. 7A with an external covering from a front elevation view.

FIG. 9C schematically shows the representative system of FIG. 7A with an external covering from a side view.

DETAILED DESCRIPTION

A. Definitions

Before describing the invention in detail, it is to be understood that this invention is not limited to particular sample processing units, systems, or methods, which can vary. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” also include plural referents unless the context clearly provides otherwise. Thus, for example, reference to “a sample processing unit” includes a combination of two or more sample processing units. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Further, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In describing and claiming the invention, the following terminology, and grammatical variants thereof, will be used in accordance with the definitions set forth below.

The term “amplifying” or “amplification” in the context of nucleic acids refers to the production of multiple copies of a polynucleotide, or a portion of the polynucleotide, typically starting from a small amount of the polynucleotide (e.g., a single polynucleotide molecule), where the amplification products or amplicons are generally detectable. Amplification of polynucleotides encompasses a variety of chemical and enzymatic processes. The generation of multiple DNA copies from one or a few copies of a target or template DNA molecule during a polymerase chain reaction (PCR) or a ligase chain reaction (LCR) are forms of amplification. Amplification is not limited to the strict duplication of the starting molecule. For example, the generation of multiple cDNA molecules from a limited amount of RNA in a sample using reverse transcription (RT)-PCR is a form of amplification. Furthermore, the generation of multiple RNA molecules from a single DNA molecule during the process of transcription is also a form of amplification.

The term “base composition” refers to the number of each residue comprised in an amplicon or other nucleic acid, without consideration for the linear arrangement of these residues in the strand(s) of the amplicon. The amplicon residues comprise, adenosine (A), guanosine (G), cytidine, (C), (deoxy)thymidine (T), uracil (U), inosine (I), nitroindoles such as 5-nitroindole or 3-nitropyrrole, dP or dK (Hill F et al. (1998) “Polymerase recognition of synthetic oligodeoxyribonucleotides incorporating degenerate pyrimidine and purine bases” Proc Natl Acad Sci U.S.A. 95(8):4258-63), an acyclic nucleoside analog containing 5-nitroindazole (Van Aerschot et al., Nucleosides and Nucleotides, 1995, 14, 1053-1056), the purine analog 1-(2-deoxy-beta-D-ribofuranosyl)-imidazole-4-carboxamide, 2,6-diaminopurine, 5-propynyluracil, 5-propynylcytosine, phenoxazines, including G-clamp, 5-propynyl deoxy-cytidine, deoxy-thymidine nucleotides, 5-propynylcytidine, 5-propynyluridine and mass tag modified versions thereof, including 7-deaza-2′-deoxyadenosine-5-triphosphate, 5-iodo-2′-deoxyuridine-5′-triphosphate, 5-bromo-2′-deoxyuridine-5′-triphosphate, 5-bromo-2′-deoxycytidine-5′-triphosphate, 5-iodo-2′-deoxycytidine-5′-triphosphate, 5-hydroxy-2′-deoxyuridine-5′-triphosphate, 4-thiothymidine-5′-triphosphate, 5-aza-2′-deoxyuridine-5′-triphosphate, 5-fluoro-2′-deoxyuridine-5′-triphosphate, O⁶-methyl-2′-deoxyguanosine-5′-triphosphate, N²-methyl-2′-deoxyguanosine-5′-triphosphate, 8-oxo-2′-deoxyguanosine-5′-triphosphate or thiothymidine-5′-triphosphate. In some embodiments, the mass-modified nucleobase comprises ¹⁵N or ¹³C or both ¹⁵N and ¹³C. In some embodiments, the non-natural nucleosides used herein include 5-propynyluracil, 5-propynylcytosine and inosine. Herein the base composition for an unmodified DNA amplicon is notated as A_(w)G_(x)C_(y)T_(z), wherein w, x, y and z are each independently a whole number representing the number of said nucleoside residues in an amplicon. Base compositions for amplicons comprising modified nucleosides are similarly notated to indicate the number of said natural and modified nucleosides in an amplicon. Base compositions are calculated from a molecular mass measurement of an amplicon, as described below. The calculated base composition for any given amplicon is then compared to a database of base compositions. A match between the calculated base composition and a single database entry reveals the identity of the bioagent.

The term “biopolymer” refers a biomolecule that includes at least two monomer units attached to one another. A “biomolecule” refers to an organic molecule that is made and/or used by an organism, and/or that is utilized to analyze the organism or components thereof. Exemplary biomolecules include nucleic acids, nucleotides, amino acids, polypeptides, peptides, peptide fragments, sugars, fatty acids, steroids, lipids, and combinations of these biomolecules (e.g., glycoproteins, ribonucleoproteins, or lipoproteins).

The term “captured” in the context of solid supports and target analytes refers to an analyte that is directly or indirectly joined or attached to a solid support via a covalent linkage, chelation, ionic interaction, and/or another mechanism. In some embodiments, target analytes are reversibly captured on solid supports, whereas in other embodiments, they are permanently captured.

The term “communicate” refers to the direct or indirect transfer or transmission, and/or capability of directly or indirectly transferring or transmitting, something at least from one thing to another thing. Objects “fluidly communicate” with one another when fluidic material is, or is capable of being, transferred from one object to another. In some embodiments, for example, material transfer components add and/or remove materials to/from the containers of sample processing units during a given purification process. Objects are in “magnetic communication” with one another when one object exerts or can exert a magnetic field of sufficient strength on another object to effect a change (e.g., a change in position or other movement) in the other object. In some embodiments, for example, containers (e.g., cuvettes, etc.) of sample processing units are moved sufficiently proximal to sample processing unit magnets such that magnetic fields generated by the magnets cause magnetically responsive particles (e.g., magnetically responsive beads with bound or otherwise captured nucleic acids) disposed within the containers to move and/or be retained proximal to surfaces of the containers when a given purification processing is being performed. Objects are in “sensory communication” when a characteristic or property of one object is or can be sense, perceived, or otherwise detected by another object. In certain embodiments, for example, carrier mechanisms of the systems described herein rotate the containers of sample processing units within sensory communication with detectors to detect one or more parameters (e.g., fluorescence, temperature, pH, or the like) of fluidic materials disposed in the containers.

The term “material” refers to something comprising or consisting of matter. The term “fluidic material” refers to material (such as, a liquid or a gas) that tends to flow or conform to the outline of its container.

The term “microplate” refers to a plate or other support structure that includes multiple cavities or wells that are structured to contain materials, such as fluidic materials. The wells typically have volume capacities of less than about 1.5 mL (e.g., about 1000 μL, about 800 μL, about 600 μL, about 400 μL, or less), although certain microplates (e.g., deep-well plates, etc.) have larger volume capacities, such as about 4 mL per well. Microplates can include various numbers of wells, for example, 6, 12, 24, 48, 96, 384, 1536, 3456, 9600, or more wells. In addition, the wells of a microplate are typically arrayed in a rectangular matrix. Microplates generally conform to the standards published by the American National Standards Institute (ANSI) on behalf of the Society for Biomolecular Screening (SBS), namely, ANSI/SBS 1-2004: Microplates—Footprint Dimensions, ANSI/SBS 2-2004: Microplates—Height Dimensions, ANSI/SBS 3-2004: Microplates—Bottom Outside Flange Dimensions, and ANSI/SBS 4-2004: Microplates—Well Positions, which are each incorporated by reference. Microplates are available from a various manufacturers including, e.g., Greiner America Corp. (Lake Mary, Fla., U.S.A.) and Nalge Nunc International (Rochester, N.Y., U.S.A.), among many others. Microplates are also commonly referred to by various synonyms, such as “microtiter plates,” “micro-well plates,” “multi-well containers,” and the like

The term “molecular mass” refers to the mass of a compound as determined using mass spectrometry, for example, ESI-MS. Herein, the compound is preferably a nucleic acid. In some embodiments, the nucleic acid is a double stranded nucleic acid (e.g., a double stranded DNA nucleic acid). In some embodiments, the nucleic acid is an amplicon. When the nucleic acid is double stranded the molecular mass is determined for both strands. In one embodiment, the strands may be separated before introduction into the mass spectrometer, or the strands may be separated by the mass spectrometer (for example, electro-spray ionization will separate the hybridized strands). The molecular mass of each strand is measured by the mass spectrometer.

The term “non-priority microplate” refers to a microplate that is processed or otherwise handled after at least one other microplate, or whose processing or handling is interrupted or deferred in order to process or otherwise handle at least one other microplate, in a given microplate handling system of the invention. That is, the order, schedule, or timing of processing or handling a non-priority microplate is subject to interruption or delay when a higher priority microplate is presented, such as a microplate including stat samples. In some embodiments, non-priority microplates are introduced into a given system via non-priority microplate storage units.

The term “nucleic acid molecule” refers to any nucleic acid containing molecule, including but not limited to, DNA or RNA. The term encompasses sequences that include any of the known base analogs of DNA and RNA including, but not limited to, 4-acetylcytosine, 8-hydroxy-N⁶-methyladenosine, aziridinylcytosine, pseudoisocytosine, 5-(carboxyhydroxyl-methyl)-uracil, 5-fluorouracil, 5-bromouracil, 5-carboxymethylaminomethyl-2-thiouracil, 5-carboxymethyl-aminomethyluracil, dihydrouracil, inosine, N⁶-isopentenyladenine, 1-methyladenine, 1-methylpseudo-uracil, 1-methylguanine, 1-methylinosine, 2,2-dimethyl-guanine, 2-methyladenine, 2-methylguanine, 3-methyl-cytosine, 5-methylcytosine, N⁶-methyladenine, 7-methylguanine, 5-methylaminomethyluracil, 5-methoxy-amino-methyl-2-thiouracil, beta-D-mannosylqueosine, 5′-methoxycarbonylmethyluracil, 5-methoxyuracil, 2-methylthio-N-isopentenyladenine, uracil-5-oxyacetic acid methylester, uracil-5-oxyacetic acid, oxybutoxosine, pseudouracil, queosine, 2-thiocytosine, 5-methyl-2-thiouracil, 2-thiouracil, 4-thiouracil, 5-methyluracil, N-uracil-5-oxyacetic acid methylester, uracil-5-oxyacetic acid, pseudouracil, queosine, 2-thiocytosine, and 2,6-diaminopurine.

The term “priority microplate” refers to a microplate that is processed or otherwise handled before the processing or handling of a non-priority microplate is commenced or completed in a given microplate handling system of the invention. In some embodiments, one or more wells of priority microplates comprise stat or urgent samples. In certain embodiments, priority microplates are introduced into a given system via priority microplate storage units.

The phrase “solid support” refers to a solid material that can be derivatized with, or otherwise attached to, a chemical or biochemical moiety. Exemplary solid supports that are optionally utilized include matrices and particles free in solution, such as glass (e.g., controlled pore glass (CPG)), nitrocellulose, polyacrylate, nylon, mixed polymers, silane polypropylene, polystyrene, magnetically attractable or responsive particles (e.g., magnetic spheres or beads), and the like.

The term “system” refers a group of objects and/or devices that form a network for performing a desired objective. In some embodiments, for example, sample processing units having fluidic materials with magnetically responsive particles are included as part of systems in which nucleic acids are purified using the magnetically responsive particles such that the molecular masses of the nucleic acids can be more readily detected by mass spectrometers of these systems.

II. Introduction

The invention relates to sample purification, and in various embodiments provides sample processing units, carrier mechanisms, sample processing stations, systems, and related methods that are useful for this purpose. The sample processing units and related aspects of the invention can be used, or adapted for use, in a wide variety of sample purification processes. In certain embodiments, for example, microplates comprising nucleic acid amplification reaction mixtures are loaded into microplate storage units of a microplate handling system. In some of these embodiments, a microplate transport mechanism of the system transports the microplates to a microplate processing area, where a material transfer component transfers aliquots of the reaction mixtures from the wells of the microplates to a sample processing system. In these embodiments, the sample processing system is typically used to purify amplification products or amplicons in the reaction mixture aliquots for subsequent detection or other analysis. To further illustrate, in some of these embodiments, the molecular masses of these purified amplicons are measured using a mass spectrometer, e.g., an electrospray ionization time-of-flight mass spectrometer or the like. The base compositions of the amplicons are typically determined from the measured molecular masses and correlated with an identity or source of target nucleic acids in the amplification reaction mixtures, such as a pathogenic organism.

Particular embodiments of molecular mass-based detection methods and other aspects that are optionally adapted for use with the sample processing units and related aspects of the invention are described in various patents and patent applications, including, for example, U.S. Pat. Nos. 7,108,974; 7,217,510; 7,226,739; 7,255,992; 7,312,036; and 7,339,051; and US patent publication numbers 2003/0027135; 2003/0167133; 2003/0167134; 2003/0175695; 2003/0175696; 2003/0175697; 2003/0187588; 2003/0187593; 2003/0190605; 2003/0225529; 2003/0228571; 2004/0110169; 2004/0117129; 2004/0121309; 2004/0121310; 2004/0121311; 2004/0121312; 2004/0121313; 2004/0121314; 2004/0121315; 2004/0121329; 2004/0121335; 2004/0121340; 2004/0122598; 2004/0122857; 2004/0161770; 2004/0185438; 2004/0202997; 2004/0209260; 2004/0219517; 2004/0253583; 2004/0253619; 2005/0027459; 2005/0123952; 2005/0130196 2005/0142581; 2005/0164215; 2005/0266397; 2005/0270191; 2006/0014154; 2006/0121520; 2006/0205040; 2006/0240412; 2006/0259249; 2006/0275749; 2006/0275788; 2007/0087336; 2007/0087337; 2007/0087338 2007/0087339; 2007/0087340; 2007/0087341; 2007/0184434; 2007/0218467; 2007/0218467; 2007/0218489; 2007/0224614; 2007/0238116; 2007/0243544; 2007/0248969; WO2002/070664; WO2003/001976; WO2003/100035; WO2004/009849; WO2004/052175; WO2004/053076; WO2004/053141; WO2004/053164; WO2004/060278; WO2004/093644; WO 2004/101809; WO2004/111187; WO2005/023083; WO2005/023986; WO2005/024046; WO2005/033271; WO2005/036369; WO2005/086634; WO2005/089128; WO2005/091971; WO2005/092059; WO2005/094421; WO2005/098047; WO2005/116263; WO2005/117270; WO2006/019784; WO2006/034294; WO2006/071241; WO2006/094238; WO2006/116127; WO2006/135400; WO2007/014045; WO2007/047778; WO2007/086904; and WO2007/100397; WO2007/118222, which are each incorporated by reference as if fully set forth herein.

Exemplary molecular mass-based analytical methods and other aspects of use in the sample processing units and systems described herein are also described in, e.g., Ecker et al. (2005) “The Microbial Rosetta Stone Database: A compilation of global and emerging infectious microorganisms and bioterrorist threat agents” BMC Microbiology 5(1):19; Ecker et al. (2006) “The Ibis T5000 Universal Biosensor: An Automated Platform for Pathogen Identification and Strain Typing” JALA 6(10:341-351; Ecker et al. (2006) “Identification of Acinetobacter species and genotyping of Acinetobacter baumannii by multilocus PCR and mass spectrometry” J Clin Microbiol. 44(8):2921-32; Ecker et al. (2005) “Rapid identification and strain-typing of respiratory pathogens for epidemic surveillance” Proc Natl Acad Sci USA. 102(22):8012-7; Hannis et al. (2008) “High-resolution genotyping of Campylobacter species by use of PCR and high-throughput mass spectrometry” J Clin Microbiol. 46(4):1220-5; Blyn et al. (2008) “Rapid detection and molecular serotyping of adenovirus by use of PCR followed by electrospray ionization mass spectrometry” J Clin Microbiol. 46(2):644-51; Sampath et al. (2007) “Global surveillance of emerging Influenza virus genotypes by mass spectrometry” PLoS ONE 2(5):e489; Sampath et al. (2007) “Rapid identification of emerging infectious agents using PCR and electrospray ionization mass spectrometry” Ann N Y Acad. Sci. 1102:109-20; Hall et al. (2005) “Base composition analysis of human mitochondrial DNA using electrospray ionization mass spectrometry: a novel tool for the identification and differentiation of humans” Anal Biochem. 344(1):53-69; Hofstadler et al. (2003) “A highly efficient and automated method of purifying and desalting PCR products for analysis by electrospray ionization mass spectrometry” Anal Biochem. 316:50-57; Hofstadler et al. (2006) “Selective ion filtering by digital thresholding: A method to unwind complex ESI-mass spectra and eliminate signals from low molecular weight chemical noise” Anal Chem. 78(2):372-378; and Hofstadler et al. (2005) “TIGER: The Universal Biosensor” Int J Mass Spectrom. 242(1):23-41, which are each incorporated by reference.

In addition to the molecular mass and base composition analyses referred to above, essentially any other nucleic acid amplification technological process is also optionally adapted for use in the systems of the invention. Other exemplary uses of the systems and other aspects of the invention include numerous biochemical assays, cell culture purification steps, and chemical synthesis, among many others. Many of these as well as other exemplary applications of use in the systems of the invention are also described in, e.g., Current Protocols in Molecular Biology, Volumes I, II, and III, 1997 (F. M. Ausubel ed.); Perbal, 1984, A Practical Guide to Molecular Cloning; the series, Methods in Enzymology (Academic Press, Inc.); Sambrook et al., 2001, Molecular Cloning: A Laboratory Manual, Third Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.; Oligonucleotide Synthesis, 1984 (M. L. Gait ed.); Nucleic Acid Hybridization, 1985, (Hames and Higgins); Transcription and Translation, 1984 (Hames and Higgins eds.); Animal Cell Culture, 1986 (R. I. Freshney ed.); Berger and Kimmel, Guide to Molecular Cloning Techniques, Methods in Enzymology volume 152 Academic Press, Inc., San Diego, Calif. (Berger), DNA Cloning: A Practical Approach, Volumes I and II, 1985 (D. N. Glover ed.); Immobilized Cells and Enzymes, 1986 (IRL Press); Gene Transfer Vectors for Mammalian Cells, 1987 (J. H. Miller and M. P. Calos eds., Cold Spring Harbor Laboratory); and Methods in Enzymology Vol. 154 and Vol. 155 (Wu and Grossman, and Wu, eds., respectively), which are each incorporated by reference.

III. Example Sample Processing Units and Carrier Mechanisms

FIGS. 1A-D schematically illustrate a sample processing unit or components thereof according to one embodiment of the invention. As shown, sample processing unit 100 includes cuvette 102 operably connected to first motor 104 (shown as a brushless DC motor). First motor 104 (i.e., one embodiment of a rotational mechanism) is configured to rotate cuvette 102 around a central longitudinal axis of cuvette 102. As also shown, first motor 104 is operably connected to support member 106 (shown as a swing arm). First motor 104 is optionally configured (e.g., under the control of an appropriately programmed controller) to rotate cuvette 102 in at least one pulsed mode, during which a substantial portion of the time of rotation, a rate of rotation of cuvette 102 exceeds a rate of rotation of sample material in cuvette 102 such that the sample material is sheared away from a surface of cuvette 102, e.g., to effect mixing of the sample material. To further illustrate, first motor 104 is optionally configured (e.g., again under the control of an appropriately programmed controller) to rotate cuvette 102 in at least one oscillating motion, e.g., also to effect mixing of sample materials. Controllers and rotational modes are described further herein.

Support member 106 is also operably connected to second motor 108 (shown as a brushless direct current motor) via mounting bracket 110. Support member 106 includes first end 112 and second end 114. Cuvette 102 is retained proximal to first end 112 of support member 106 via first motor 104, whereas second motor 108 is operably connected to support member 106 proximal to second end 114 of support member 106. Support member 106 is configured to rotate at least partially around a rotational axis extending through and proximal to second end 114 of support member 106. Pin 116 is fixedly coupled to second end 114 of support member 106 and aligned with the rotational axis. Pin 116 is also operably coupled to second motor 108, which effects rotation of cuvette 102 between second position 118 (e.g., a cuvette rotational or spin position) and first position 120 via pin 116 and support member 106. Collectively, second motor 108, pin 116, and support member 106 are components of one embodiment of an exemplary conveyance mechanism. As additionally shown, sample processing unit 100 includes circuitry 122 that electrically connects to first motor 104, second motor 108, and a controller or power source (not shown) to effect control of first motor 104 and second motor 108.

Sample processing unit 100 also includes magnets 124 (shown as permanent magnets) attached to magnet mounting arm 126, e.g., to facilitate certain processing steps that involve magnetically-based separation of materials. In some embodiments, electromagnets are utilized. Magnet mounting arm 126 is operably connected to mounting bracket 110 and holds magnets 124 in substantially fixed positions relative to cuvette 102 and support member 106. Magnets 124 are disposed proximal to receiving space 126. As illustrated, for example, in FIGS. 1 B and C, when cuvette 102 is in first position 120, cuvette 102 is located at least partially within receiving space 128.

In certain embodiments, the sample processing unit includes only a single magnet attached to mounting bracket via a magnet mounting arm in a substantially fixed positions relative to a cuvette, support member, and first motor. In addition to a support member, the conveyance mechanism of an exemplary sample processing unit may also include a second motor, which conveys a cuvette between a first position and a second position.

The conveyance mechanisms of the sample processing units of the invention include various embodiments. As mentioned above, in certain embodiments, conveyance mechanisms are configured to rotate cuvettes or other types of containers between selected positions (e.g., between spin mixing, detection, and magnetic particle retention positions). Essentially any other mechanism that can convey containers to and from being within magnetic communication with the magnets of the sample processing units described herein is optionally utilized. As a further illustration, conveyance mechanisms include slidable support members in some embodiments. As shown in FIGS. 3A and B, for example, the conveyance mechanism of sample processing unit 300 includes support member 302 and gantry or linear slide track 304. Linear drive mechanism 306 is configured to move support member 302 along linear slide track 304. Further, rotational mechanism 308 (e.g., a motor or the like) is operably coupled with container 310 via support member 302. In addition, magnet 312 is operably connected to linear slide track 304 in a substantially fixed position via magnet mounting arm 314. Support member 302 and container 310 are shown in first position 316 in FIG. 3A, whereas they are shown in second position 318 in FIG. 3B.

In certain embodiments, carrier mechanisms are operably connected to sample processing units. Carrier mechanisms are typically configured to move sample processing units to one or more locations, e.g., where various processing steps are performed, such as adding and/or removing fluidic materials from sample processing unit containers. Typically, multiple sample processing units are included on a given carrier mechanism, e.g., to enhance the throughput of sample processing applications performed using the carrier mechanism. In some embodiments, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, or more sample processing units are included on a given carrier mechanism. In addition, essentially any carrier mechanism format that can be used to move sample processing units to selected locations is optionally utilized. In some embodiments, for example, a carrier mechanism includes a carousel that is configured to rotate sample processing units to selected locations. In another representative embodiment, a carrier mechanism includes a conveyor track that is configured to convey sample processing units to one or more locations as desired. Both of these exemplary carrier mechanism embodiments are described further herein. To further illustrate, manifolds for substantially simultaneously distributing fluidic materials to and/or from the containers of multiple sample processing units of a given carrier mechanism are included in certain embodiments, e.g., to enhance process throughput.

One embodiment of a carrier mechanism with a manifold is schematically depicted in FIG. 4 A-F from various points of view. As shown, carousel 400 includes 22 sample processing units 100 mounted on circular support structure 402, which is operably connected to rotating assembly 404. Rotating assembly 404 includes a slip ring or rotary electrical interface that effects rotation of circular support structure 402 and sample processing units 100 to selected positions around carousel 400. Rotating assembly 404 is mounted on support base 406, which provides structural support to carousel 400. Carousel 400 control includes motor 408 (e.g., a stepper motor, such as a Model No. 5704M-10 or 5709L-06PD available from Lin Engineering, Santa Clara, Calif., U.S.A.) and one or more transmissive photomicrosensors (e.g., a Model No. EE-SX1071 available from Omron Electronics LLC, Schaumburg, Ill., U.S.A.).

As additionally shown, sample cleanup station or manifold 410 is also mounted above carousel 400 on manifold support structure 412, which is connected to rotating assembly 404 and manifold support pillars 414. Manifold 410 is used to aspirate and dispense fluidic materials from/into cuvettes 102 of sample processing units 100 as part of sample purification procedures. More specifically, manifold 410 includes aspirate heads 416 and dispense heads 418. Aspirate heads 416 typically fluidly communicate with fluidic material waste containers (not within view) via flexible tubing, whereas dispense heads 418 generally fluidly communicate with fluidic material sources or reservoirs via flexible tubing. Fluidic material is typically conveyed through the tubing using a fluid conveyance mechanism, such as a pump (e.g., a peristaltic pump, a vacuum pump, or the like). Manifold motor and linear motion component 420, which includes manifold stepper motor (e.g., a Model No. 211-13-02 or 211-20-02 available from Lin Engineering, Santa Clara, Calif., U.S.A.), is configured to raise and lower manifold plate 424. As shown, aspirate heads 416 are mounted on manifold plate 424. When fluidic materials are aspirated from cuvettes 102, rotating assembly 404 typically rotates selected cuvettes 102 into alignment with selected aspirate heads 416. Manifold motor and linear motion component 420 then typically lowers aspirate heads 416 such that needles of aspirate heads 416 contact fluidic materials disposed within the selected cuvettes 102 so that selected volumes of the fluidic materials can be aspirated from the selected cuvettes 102. In some of these embodiments, magnetically responsive particles (with bound or otherwise captured nucleic acids or other analytes) are included in the fluidic materials. In these embodiments, the selected cuvettes 102 are typically moved into magnetic communication with magnets 124 of the corresponding sample processing units 100 so that the magnetically responsive particles are retained within the selected cuvettes 102 as the selected aliquots are removed through the needles of the selected aspirate heads 416. After a given fluidic material aspiration step is performed, manifold motor and linear motion component 420 typically raises manifold plate 424 and aspirate heads 416 a sufficient distance such that rotating assembly 404 can rotate cuvettes 102 to other locations without contacting the needles of aspirate heads 416. As further illustrated, dispense heads 418 are mounted in substantially fix positions on manifold support structure 412 such that they can fluidly communicate with cuvettes 102 when cuvettes 102 are positioned beneath and aligned with the needles of dispense heads 418. During operation, e.g., before or after a given aspiration step is performed, rotating assembly 404 typically rotates selected cuvettes 102 into alignment with selected dispense heads 418 so that selected volumes of fluidic material (e.g., reagent mixtures, elution buffers, etc.) can be dispensed into the selected cuvettes 102. Before or after a given aspiration or dispensing step is performed, selected cuvettes 102 are typically spun using first motors 104 of sample processing units 100 to mix fluidic materials in the selected cuvettes 102. Exemplary systems that include carousels and manifolds are described further herein.

To illustrate another exemplary embodiment, FIGS. 5 A and B schematically depict a carrier mechanism that includes a conveyor track from top and side elevation views, respectively. As shown, carrier mechanism 500 includes conveyor track 502 (e.g., a conveyor belt, etc.), which is configured to rotate counter-clockwise around rotational couplings 504 (e.g., pulleys or the like). Sample processing units 506, which include containers 508, are connected to conveyor track 502. During operation, rotational couplings 504 rotate sample processing units 506 to fluid transfer stations 510, 512, and 516, which include fluid transfer heads 518, 520, and 522, respectively, that each have an aspirate/dispense needle. Fluid transfer heads 518, 520, and 522 are configured to be raised and lowered. As shown, for example, in FIG. 5B, when sample processing units 506 are aligned beneath fluid transfer heads 518, 520, and 522, the heads are typically lowered so that the aspirate/dispense needles can fluidly communicate with containers 508. Note that the container of the sample processing unit depicted on the near side of conveyor track 502 in FIG. 5B partially obscures the needle of fluid transfer head 520, which is lowered into the container of the sample processing unit (not within view in FIG. 5B) on the far side of conveyor track 502. When sample processing units 506 are rotated around rotational couplings 504, transfer heads 518, 520, and 522 are typically raised a sufficient height to permit the unobstructed passage of containers 508 beneath the needles of transfer heads 518, 520, and 522. As also shown, transfer heads 518 and 522 are also configured to move along gantry tracks 524 and 526, respectively.

IV. Example Controllers and Related Systems

Controllers are typically operably connected to sample processing units and carrier mechanisms, whether they are used as stand-alone sample processing stations or as system components. The controllers of the sample processing stations and systems described herein are generally configured to effect, e.g. the rotation of sample processing unit containers to mix sample materials in the containers (e.g., in various selectable modes of rotation, etc.), the movement of containers to and from being within magnetic communication with the magnets of sample processing units, the movement of carrier mechanisms to position sample processing units relative to material transfer components, the transfer of materials to and from the containers of sample processing units, the detection of one or more parameters of sample materials disposed in the containers of sample processing units or of aliquots of those materials taken from those containers, and the like. Controllers are typically operably connected to one or more system components, such as motors (e.g., via motor drives), thermal modulating components, detectors, motion sensors, fluidic handling components, robotic translocation devices, or the like, to control operation of these components. More specifically, controllers are generally included either as separate or integral system components that are utilized to effect, e.g., the rotation of the containers of sample processing units according to one or more selectable rotational modes, the transfer of materials to and/or from the containers of sample processing units, the detection and/or analysis of detectable signals received from sample materials by detectors, etc. Controllers and/or other system components is/are generally coupled to an appropriately programmed processor, computer, digital device, or other logic device or information appliance (e.g., including an analog to digital or digital to analog converter as needed), which functions to instruct the operation of these instruments in accordance with preprogrammed or user input instructions (e.g., mixing mode selection, fluid volumes to be conveyed, etc.), receive data and information from these instruments, and interpret, manipulate and report this information to the user.

A controller or computer optionally includes a monitor which is often a cathode ray tube (“CRT”) display, a flat panel display (e.g., active matrix liquid crystal display, liquid crystal display, etc.), or others. Computer circuitry is often placed in a box, which includes numerous integrated circuit chips, such as a microprocessor, memory, interface circuits, and others. The box also optionally includes a hard disk drive, a floppy disk drive, a high capacity removable drive such as a writeable CD-ROM, and other common peripheral elements. Inputting devices such as a keyboard or mouse optionally provide for input from a user. An exemplary system comprising a computer is schematically illustrated in FIG. 6.

The computer typically includes appropriate software for receiving user instructions, either in the form of user input into a set of parameter fields, e.g., in a GUI, or in the form of preprogrammed instructions, e.g., preprogrammed for a variety of different specific operations. The software then converts these instructions to appropriate language for instructing the operation of one or more controllers to carry out the desired operation, e.g., rotating sample processing unit containers to mix sample materials in the containers, aspirating fluidic materials from sample processing unit containers, dispensing materials into sample processing unit containers, or the like. The computer then receives the data from, e.g., sensors/detectors included within the system, and interprets the data, either provides it in a user understood format, or uses that data to initiate further controller instructions, in accordance with the programming, e.g., such as in monitoring detectable signal intensity, rates or modes of sample processing unit container rotation, or the like.

More specifically, the software utilized to control the operation of the sample processing stations and systems of the invention typically includes logic instructions that selectively direct, e.g., motors to rotate cuvettes in pulsed modes, during which a substantial portion of the time of rotation, a rate of rotation of the cuvettes exceeds a rate of rotation of the samples in the cuvettes such that the samples are sheared away from surfaces of the cuvettes to effect sample mixing, motors to rotate the cuvettes in oscillating motions, and the like. The logic instructions of the software are typically embodied on a computer readable medium, such as a CD-ROM, a floppy disk, a tape, a flash memory device or component, a system memory device or component, a hard drive, a data signal embodied in a carrier wave, and/or the like. Other computer readable media are known to persons of skill in the art. In some embodiments, the logic instructions are embodied in read-only memory (ROM) in a computer chip present in one or more system components, without the use of personal computers.

The computer can be, e.g., a PC (Intel x86 or Pentium chip-compatible DOS™, OS2™, WINDOWST™, WINDOWS NT™, WINDOWS98™, WINDOWS2000™, WINDOWS XP™, WINDOWS Vista™, LINUX-based machine, a MACINTOSHT™, Power PC, or a UNIX-based (e.g., SUN™ work station) machine) or other common commercially available computer which is known to one of skill. Standard desktop applications such as word processing software (e.g., Microsoft Word™ or Corel WordPerfect™) and database software (e.g., spreadsheet software such as Microsoft Exce1™, Corel Quattro Pro™, or database programs such as Microsoft Access™ or Paradox™) can be adapted to the present invention. Software for performing, e.g., sample processing unit container rotation, material conveyance to and/or from sample processing unit containers, mixing process monitoring, assay detection, and data deconvolution is optionally constructed by one of skill using a standard programming language such as Visual basic, C, C++, Fortran, Basic, Java, or the like.

The sample processing stations and related systems of the invention optionally include detectors or detection components configured to detect one or more detectable signals or parameters from a given process, e.g., from materials disposed within sample processing unit container or taken therefrom. In some embodiments, systems are configured to detect detectable signals or parameters that are upstream and/or downstream of a given process involving the sample processing units described herein. Suitable signal detectors that are optionally utilized in these systems detect, e.g., pH, temperature, pressure, density, salinity, conductivity, fluid level, radioactivity, luminescence, fluorescence, phosphorescence, molecular mass, emission, transmission, absorbance, and/or the like. In some embodiments, the detector monitors a plurality of signals, which correspond in position to “real time” results. Example detectors or sensors include PMTs, CCDs, intensified CCDs, photodiodes, avalanche photodiodes, optical sensors, scanning detectors, or the like. Each of these as well as other types of sensors is optionally readily incorporated into the sample processing stations and systems described herein. The detector optionally moves relative to the stations, sample containers or other assay components, or alternatively, the stations, sample containers or other assay components move relative to the detector. Optionally, the stations and systems of the invention include multiple detectors. In these stations and systems, such detectors are typically placed either in or adjacent to, e.g., a sample processing unit cuvette or other vessel, such that the detector is in sensory communication with the sample processing unit cuvette or other vessel (i.e., the detector is capable of detecting the property of the cuvette or vessel or portion thereof, the contents of a portion of the cuvette or vessel, or the like, for which that detector is intended).

The detector optionally includes or is operably linked to a computer, e.g., which has system software for converting detector signal information into assay result information or the like. For example, detectors optionally exist as separate units, or are integrated with controllers into a single instrument. Integration of these functions into a single unit facilitates connection of these instruments with the computer, by permitting the use of a few or even a single communication port for transmitting information between system components. Detection components that are optionally included in the systems of the invention are described further in, e.g., Skoog et al., Principles of Instrumental Analysis, 6^(th) Ed., Brooks Cole (2006) and Curren, Analytical Instrumentation:

Performance Characteristics and Quality, John Wiley & Sons, Inc. (2000), which are both incorporated by reference.

The sample processing stations and systems of the invention optionally also include at least one robotic translocation or gripping component that is structured to grip and translocate containers or other processing components between components of the stations or systems and/or between the stations or systems and other locations (e.g., other work stations, etc.). A variety of available robotic elements (robotic arms, movable platforms, etc.) can be used or modified for use with these systems, which robotic elements are typically operably connected to controllers that control their movement and other functions.

FIG. 6 is a schematic showing a representative system including an information appliance in which various aspects of the present invention may be embodied. Other exemplary systems are also described herein. As will be understood by practitioners in the art from the teachings provided herein, the invention is optionally implemented in hardware and software. In some embodiments, different aspects of the invention are implemented in either client-side logic or server-side logic. As will also be understood in the art, the invention or components thereof may be embodied in a media program component (e.g., a fixed media component) containing logic instructions and/or data that, when loaded into an appropriately configured computing device, cause that apparatus or system to perform according to the invention. As will additionally be understood in the art, a fixed media containing logic instructions may be delivered to a viewer on a fixed media for physically loading into a viewer's computer or a fixed media containing logic instructions may reside on a remote server that a viewer accesses through a communication medium in order to download a program component.

FIG. 6 shows information appliance or digital device 600 that may be understood as a logical apparatus (e.g., a computer, etc.) that can read instructions from media 617 and/or network port 619, which can optionally be connected to server 620 having fixed media 622. Information appliance 600 can thereafter use those instructions to direct server or client logic, as understood in the art, to embody aspects of the invention. One type of logical apparatus that may embody the invention is a computer system as illustrated in 600, containing CPU 607, optional input devices 609 and 611, disk drives 615 and optional monitor 605. Fixed media 617, or fixed media 622 over port 619, may be used to program such a system and may represent a disk-type optical or magnetic media, magnetic tape, solid state dynamic or static memory, or the like. In specific embodiments, the aspects of the invention may be embodied in whole or in part as software recorded on this fixed media. Communication port 619 may also be used to initially receive instructions that are used to program such a system and may represent any type of communication connection. Optionally, aspects of the invention are embodied in whole or in part within the circuitry of an application specific integrated circuit (ACIS) or a programmable logic device (PLD). In such a case, aspects of the invention may be embodied in a computer understandable descriptor language, which may be used to create an ASIC, or PLID.

In addition, FIG. 6 also shows sample processing station 602, which is operably connected to information appliance 600 via server 620. Optionally, sample processing station 602 is directly connected to information appliance 600. During operation, sample processing station 602 typically mixes and retains selected materials (e.g., magnetically responsive particles with captured target materials, etc.) in the cuvettes of the sample processing units of sample processing station 602, e.g., as part of an assay or other process. FIG. 6 also shows material transfer component 623 and detector 624, which are optionally included in the systems of the invention. As shown, material transfer component 623 and detector 624 are operably connected to information appliance 600 via server 620. In some embodiments, material transfer component 623 and/or detector 624 is directly connected to information appliance 600. Material transfer component 623 is typically configured to transfer materials to and/or from the cuvettes of the sample processing units of sample processing station 602. In certain embodiments, detector 624 is configured to detect detectable signals produced in the cuvettes of the sample processing units of sample processing station 602 or in aliquots of materials removed from and/or to be added to those cuvettes.

V. Example Sample Processing System and Related Process Embodiments

To further illustrate exemplary embodiments of the invention, FIG. 7 A-G schematically depict a portion of a representative system for nucleic acid amplification product desalting and molecular mass measurement that includes a sample processing station as a sub-system component. The measured molecular masses of the amplification products are typically used to determine base compositions of the corresponding amplification products, which are then generally correlated with the identities or organismal sources of the initial template nucleic acids, for example, as part of a research or in-vitro diagnostic application, among many others.

As shown in FIG. 7 A-G, components of representative system 700 include microplate handling component or system 10, material transfer component 702, mixing station 704, wash stations 706 and 708, sample processing component 710, and sample injector 712. During operation, microplates are typically stored or positioned in input non-priority microplate storage unit 12, output non-priority microplate storage unit 14, priority microplate storage unit 16, microplate processing area 18, and non-priority microplate holding area 20 (e.g., on non-priority microplate holding component 22) of microplate handling component 10. As also shown, microplate handling component 10 also includes barcode reader 36. In the exemplary embodiment shown, barcode reader 36 is configured to read barcodes disposed on microplates when the microplates are disposed in or proximal to non-priority microplate holding area 20, e.g., to track the microplates or samples contained in the microplates in microplate handling system 10. In some embodiments, for example, non-priority microplates are stored in input non-priority microplate storage unit 12 and priority microplates are stored in priority microplate storage unit 16 after target regions of template nucleic acids in those plates have been amplified, e.g., at a separate thermocycling station or nucleic acid amplification component. Essentially any thermal cycling station or device is optionally adapted for use with a system of the invention, such as system 700. Examples of suitable thermocycling devices that are optionally utilized are available from many different commercial suppliers, including Mastercycler® devices (Eppendorf North America, Westbury, N.Y., U.S.A.), the COBAS® AMPLICOR Analyzer (Roche Molecular Systems, Inc., Pleasanton, Calif., U.S.A.), Mycycler and iCycler Thermal Cyclers (Bio-Rad Laboratories, Inc., Hercules, Calif., U.S.A.), and the SmartCycler System (Cepheid, Sunnyvale, Calif., U.S.A.), among many others. In other exemplary embodiments, sample preparation components, nucleic acid amplification components, and related fluid handling or material transfer components are integrated with the systems described herein, e.g., to fully automate a given nucleic acid amplification and analysis process. Instruments that can be adapted for this purpose include, for example, the m2000™ automated instrument system (Abbott Laboratories, Abbott Park, Ill., U.S.A.), the GeneXpert System (Cepheid, Sunnyvale, Calif. U.S.A.), and the COBAS® AmpliPrep® System (Roche Molecular Systems, Inc., Pleasanton, Calif., U.S.A.), and the like.

Microplates are transferred from input non-priority microplate storage unit 12 or priority microplate storage unit 16 to microplate processing area 18 using platform 28 of a microplate transport mechanism. As referred to above and as shown in, e.g., FIGS. 7 F and G, platform 28 is operably connected to X-axis linear motion component 38. X-axis linear motion component 38 includes gantry 40. Platform 28 is operably connected to carriage 42, which moves along gantry 40, driven by motor 89. As further shown in FIGS. 7 F and G, microplate transport mechanism 26 also includes Y-axis linear motion component 44 operably connected to carriage 42 and to platform 28. Y-axis linear motion component 44 is configured to raise and lower platform 28 along the Y-axis. Suitable linear motion components, motors, and motor drives are generally available from many different commercial suppliers including, e.g., Techno-Isel Linear Motion Systems (New Hyde Park, N.Y., U.S.A.), NC Servo Technology Corp. (Westland, Mich., USA), Enprotech Automation Services (Ann Arbor, Mich., U.S.A.), Yaskawa Electric America, Inc. (Waukegan, Ill., U.S.A.), ISL Products International, Ltd. (Syosset, N.Y., U.S.A.), AMK Drives & Controls, Inc. (Richmond, Va., U.S.A.), Aerotech, Inc. (Pittsburgh, Pa., U.S.A.), HD Systems Inc. (Hauppauge, N.Y., U.S.A.), and the like. Additional detail relating to motors and motor drives are described in, e.g., Polka, Motors and Drives, ISA (2002) and Hendershot et al., Design of Brushless Permanent-Magnet Motors, Magna Physics Publishing (1994), which are both incorporated by reference. Microplate handling components are also described in, e.g., U.S. Provisional Patent Application No. 61/097,523, entitled “MICROPLATE HANDLING SYSTEMS AND RELATED COMPUTER PROGRAM PRODUCTS AND METHODS” filed Sep. 16, 2008 by Hofstadler et al., which is incorporated by reference in its entirety. FIG. 7G also shows power source 98, which provides power for the system shown in this figure.

Material transfer component 702 includes sample input gantry 714 and sample output gantry 716. Input gantry head 718 is configured to move along sample input gantry 714, whereas output gantry head 720 is configured to move along sample output gantry 716. Input gantry head 718 and output gantry head 720 each include needles that are configured to aspirate and dispense fluidic materials. Further, input gantry head 718 and output gantry head 720 are each configured to be raised and lowered along the Y-axis. During operation of exemplary system 700, the needle or pipetting tip of input gantry head 718 is typically used to aspirate an aliquot of magnetically responsive particles (e.g., magnetically responsive beads, such as BioMag®Plus Amine superparamagnetic microparticles available from Bangs Laboratories, Inc., Fishers, Ind., U.S.A.) that bind nucleic acids from a mixing cartridge positioned at mixing station 704. Magnetically responsive particle sources and mixing stations are also described in, e.g., U.S. Provisional Patent Application No. 61/097,520, entitled “MIXING CARTRIDGES, MIXING STATIONS, AND RELATED KITS, SYSTEMS, AND METHODS” filed Sep. 16, 2008 by Hofstadler et al., which is incorporated by reference in its entirety. Nucleic acid purification involving magnetically responsive particles is also described in, e.g., U.S. Patent App. Pub. No. US 2005/0164215, entitled “METHOD FOR RAPID PURIFICATION OF NUCLEIC ACIDS FOR SUBSEQUENT ANALYSIS BY MASS SPECTROMETRY BY SOLUTION CAPTURE,” filed May 12, 2004 by Hofstadler et al., and U.S. Patent App. Pub. No. US 2005/0130196, entitled “METHOD FOR RAPID PURIFICATION OF NUCLEIC ACIDS FOR SUBSEQUENT ANALYSIS BY MASS SPECTROMETRY BY SOLUTION CAPTURE,” filed Sep. 17, 2004 by Hofstadler et al., which are both incorporated by reference in their entirety. Optionally before, but typically after aspirating the aliquot of magnetically responsive particles (e.g., to minimize the possibility of cross-contaminating samples), the needle of input gantry head 718 is also generally used to aspirate an aliquot of an amplification product sample from a selected well of a microplate positioned in microplate processing area 18 of microplate handling system 10. The resulting mixture of magnetically responsive particle and amplification product sample aliquots disposed within the needle of input gantry head 718 is then typically transferred to sample processing component 710 along sample input gantry 714. After dispensing the mixture at sample processing component 710, the needle of input gantry head 718 is typically washed at wash station 706, e.g., to minimize the probability of cross-contaminating samples, prior to repeating this transfer cycle for other amplification product samples contained in the wells of a given microplate (e.g., priority or non-priority microplates) positioned in microplate processing area 18 of microplate handling system 10.

In the embodiment shown, sample processing station or component 710 is a desalting station that is used to desalt or otherwise purify nucleic acid amplification products in the sample mixture prior to mass spectrometric analysis. Sample processing component 710 includes carrier mechanism 722 (shown as a carousel), which includes a plurality of sample processing units 724. In the illustrated embodiment, each sample processing unit 724 includes cuvette 726 and magnet 728. After a mixture of magnetically responsive particle and amplification product sample aliquots is dispensed into a given cuvette 726, that cuvette is typically rotated in a counter-clockwise direction on carrier mechanism 722 to various positions within sample processing component 710 where various reagents (e.g., washes with ammonium bicarbonate and/or MeOH, etc.) are added to and/or removed from that cuvette (e.g., via various fluidic handling components of manifold 730) as part of the process of purifying the amplification products captured or otherwise bound to the magnetically responsive particles in the mixture. When fluidic materials are removed from the cuvette at a given position within sample processing component 710, the cuvette is typically moved proximal to the magnet of the particular sample processing unit (e.g., cuvette 726 is moved proximal to magnet 728 of sample processing unit 724) using a conveyance mechanism to establish sufficient magnetic communication between the magnet and the magnetically responsive particles such that the magnetically responsive particles are moved to and retained on an internal surface of the cuvette while fluidic materials are removed from the cuvette. At the conclusion of a purification process for a given sample, the purified amplification products are then typically aspirated from the particular cuvette using the needle of output gantry head 720. During or prior this step, the nucleic acid amplification products are eluted (e.g., using a solution that includes piperidine, imidazole, MeOH, and optionally peptide calibration standards (used as part of subsequent mass spectrometric analyses), or the like) from the magnetically responsive particles. After purified amplification products have been removed from a given cuvette, that cuvette is then generally rotated on carrier mechanism 722 into communication with cuvette wash station 727, where the cuvette is washed prior to commencing another purification cycle involving the cuvette and another sample. Sample desalting/purification methods are also described in, e.g., U.S. Patent App. Pub. No. US 2005/0164215, entitled “METHOD FOR RAPID PURIFICATION OF NUCLEIC ACIDS FOR SUBSEQUENT ANALYSIS BY MASS SPECTROMETRY BY SOLUTION CAPTURE,” filed May 12, 2004 by Hofstadler et al., and U.S. Patent App. Pub. No. US 2005/0130196, entitled “METHOD FOR RAPID PURIFICATION OF NUCLEIC ACIDS FOR SUBSEQUENT ANALYSIS BY MASS SPECTROMETRY BY SOLUTION CAPTURE,” filed Sep. 17, 2004 by Hofstadler et al., and Hofstadler et al. (2003) “A highly efficient and automated method of purifying and desalting PCR products for analysis by electrospray ionization mass spectrometry” Anal Biochem. 316:50-57, which are each incorporated by reference in their entirety.

Purified and eluted amplification products that have been aspirated from a particular cuvette of sample processing component 710 are typically transported along sample output gantry 716 to sample injector 712 (shown as a two channel time-of-flight injector) using output gantry head 720. That is, the amplification products are typically dispensed from the needle or pipetting tip of output gantry head 720 into one of the two channels of sample injector 712, which generally comprise two independent sample injection syringe pumps that are configured to receive the amplification products. After dispensing the amplification products at sample injector 712, the needle of output gantry head 720 is typically washed at wash station 708 prior to aspirating another purified amplification product sample from sample processing component 710, e.g., to reduce the potential for carryover contamination between samples.

Now referring to FIG. 8, which schematically shows additional components of representative system 700 (sample processing component 710 is not shown so that other system components are within view) from a perspective view. As shown, the additional components include dual sprayer module 732, which includes two independent electrospray ionization sprayers, and time-of-flight mass spectrometer 734. Amplification product samples received at sample injector 712 are typically injected into one of the two sprayers of dual sprayer module 732 for electrospray ionization and mass measurement in time-of-flight mass spectrometer 734. As further shown, the additional components of representative system 700 also include input/output device 736 (shown as a touch screen monitor), computer 737, output device 739 (shown as a printer), reagent and/or waste modules 738, and chassis 740. Input/output device 736, computer 737, and output device 739 are components of a controller of system 700. Controllers are described further herein. Reagent module 738 provides reagent sources, and the waste module 738 provides waste receptacles for system 700. Chassis 740 provides mechanical support for microplate handling system 10, sample processing component 710, and other components of system 700. To further illustrate, FIGS. 11A-C schematically show representative system 700 with an external covering from various views.

In some embodiments, the base compositions of amplification products are determined from detected molecular masses. In these embodiments, base compositions are typically correlated with the identity of an organismal source, genotype, or other attribute of the corresponding template nucleic acids in a given sample. Suitable software and related aspects, e.g., for determining base compositions from detected molecular masses and for performing other aspects of base composition analysis are commercially available from Ibis Biosciences, Inc. (Carlsbad, Calif., U.S.A.). Nucleic acid base composition analysis is also described in many of the publications referred to herein, including, e.g., U.S. Pat. No. 7,255,992, entitled “METHODS FOR RAPID DETECTION AND IDENTIFICATION OF BIOAGENTS FOR ENVIRONMENTAL AND PRODUCT TESTING,” which issued Aug. 14, 2007 to Ecker et al., U.S. Pat. No. 7,226,739, entitled “METHODS FOR RAPID DETECTION AND IDENTIFICATION OF BIOAGENTS IN EPIDEMIOLOGICAL AND FORENSIC INVESTIGATIONS,” which issued Jun. 5, 2007 to Ecker et al., U.S. Pat. No. 7,217,510, entitled “METHODS FOR PROVIDING BACTERIAL BIOAGENT CHARACTERIZING INFORMATION,” which issued May 15, 2007 to Ecker et al., and U.S. Pat. No. 7,108,974, entitled “METHOD FOR RAPID DETECTION AND IDENTIFICATION OF BIOAGENTS,” which issued Sep. 19, 2006 to Ecker et al., which are each incorporated by reference in their entirety.

VI. Fabrication Methods and Materials

Sample processing units or components thereof, carrier mechanisms or components thereof, and station or system components (e.g., mixing stations, microplate storage units, microplate transport mechanisms, support bases, etc.) are optionally formed by various fabrication techniques or combinations of such techniques including, e.g., machining, embossing, extrusion, stamping, engraving, injection molding, cast molding, etching (e.g., electrochemical etching, etc.), or other techniques. These and other suitable fabrication techniques are generally known in the art and described in, e.g., Molinari et al. (Eds.), Metal Cutting and High Speed Machining, Kluwer Academic Publishers (2002), Altintas, Manufacturing Automation: Metal Cutting Mechanics, Machine Tool Vibrations, and CNC Design, Cambridge University Press (2000), Stephenson et al., Metal Cutting Theory and Practice, Marcel Dekker (1997), Fundamentals of Injection Molding, W.

J. T. Associates (2000), Whelan, Injection Molding of Thermoplastics Materials, Vol. 2, Chapman & Hall (1991), Rosato, Injection Molding Handbook, 3^(rd) Ed., Kluwer Academic Publishers (2000), Fisher, Extrusion of Plastics, Halsted Press (1976), and Chung, Extrusion of Polymers: Theory and Practice, Hanser-Gardner Publications (2000), which are each incorporated by reference. Exemplary materials optionally used to fabricate sample processing units, carrier mechanisms, manifolds, or components thereof include metal (e.g., steel, aluminum, etc.), glass, polymethylmethacrylate, polyethylene, polydimethylsiloxane, polyetheretherketone, polytetrafluoroethylene, polystyrene, polyvinylchloride, polypropylene, polysulfone, polymethylpentene, and polycarbonate, among many others. In certain embodiments, following fabrication, system components are optionally further processed, e.g., by coating surfaces with a hydrophilic coating, a hydrophobic coating (e.g., a Xylan 1010DF/870 Black coating available from Whitford Corporation (West Chester, Pa.), etc.), or the like, e.g., to prevent interactions between component surfaces and reagents, samples, or the like.

VII. Examples

It is understood that the examples and embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the claimed invention. It is also understood that various modifications or changes in light the examples and embodiments described herein will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.

I. PCR Product Purification and Desalting Example

1. PCR Product Purification

PCR products were thoroughly purified and desalted before ESI MS. This step typically precedes ESI-MS analysis, because PCR salts and buffer components generally have a deleterious effect on the ESI process. Even small amounts of salts (<1 μmol/L) will typically significantly reduce ESI sensitivity, owing to the appearance of multiple cation adducts in the mass spectra. The protocol used in this example is based on a weak anion-exchange method, in which amplified DNA was bound to a weak anion-exchange resin coated on the outside of magnetic bead particles. Unconsumed deoxynucleoside triphosphates, salts, and other low-molecular-weight species that could interfere with subsequent ESI-MS analysis were removed using a sample processing station system described herein and the PCR cleanup process outlined as follows:

-   1. Loaded 40 μL PCR Product and 50 μL magnetic bead solution into a     clean cuvette; -   2. Mixed the beads for 4.5 minutes to allow the DNA to bind the     magnetic beads; -   3. Positioned the cuvette at the magnet for 30 seconds to separate     the beads from the solution; -   4. Aspirated the liquid from the cuvette and dispensed 80 μL of 100     mM ammonium bicarbonate in a 50:50 methanol:water solution; -   5. Resuspended and washed the beads by mixing for 35 seconds; -   6. Positioned the cuvette at the magnet for 15 seconds to separate     the beads from the solution; -   7. Aspirated the liquid from the cuvette and dispensed 80 μL of 100     mM ammonium bicarbonate in a 50:50 methanol:water solution; -   8. Resuspended and washed the beads by mixing for 35 seconds; -   9. Positioned the cuvette at the magnet for 15 seconds to separate     the beads from the solution; -   10. Aspirated the liquid from the cuvette and dispensed 80 μL of     50:50 methanol:water solution; -   11. Resuspended and washed the beads by mixing for 35 seconds; -   12. Positioned the cuvette at the magnet for 15 seconds to separate     the beads from the solution; -   13. Aspirated the liquid from the cuvette and dispensed 40 μL of 25     mM piperidine and 25 mM imidazole in 35:65 methanol:water solution; -   14. Resuspended the magnetic beads and allowed time for the DNA to     elute from the beads for 2 minutes; -   15. Positioned the cuvette at the magnet for 30 seconds to separate     the beads from the solution; and -   16. Aspirated the solution and injected into the ESI-MS for     analysis.     TOTAL PCR PRODUCT CLEANUP TIME=10 minutes     II. 2. Cuvette Cleaning Protocol

The cuvette cleaning protocol utilized to clean the cuvette after PCR products were purified and desalted was as follows:

-   1. Dispensed 160 μL of 25 mM piperidine and 25 mM imidazole in 35:65     methanol:water solution and mixed for 15 seconds; -   2. Aspirated solution and dispensed 160 μL of clean (Type I) water     into the cuvette; -   3. Mixed for 15 seconds; and -   4. Aspirated liquid from cuvette.     TOTAL CUVETTE CLEANUP TIME=2 minutes     II. 3. ESI-TOF Mass Spectrometry

A Bruker Daltonics (Billerica, Mass., U.S.A.) MicroTOF-ESI time-of-flight (TOF) mass spectrometer was used to analyze purified and desalted PCR products in this example. Ions from the ESI source underwent orthogonal ion extraction and were focused in a reflectron prior to detection. Ions were formed in the standard MicroTOF-ESI source, which was equipped with an off-axis sprayer and glass capillary. For operation in the negative ion mode, the atmospheric pressure end of the glass capillary was biased at 3500 V relative to the ESI needle during data acquisition. A countercurrent flow of dry N₂ gas was employed to assist in the desolvation process. External ion accumulation was employed to improve ionization duty cycle during data acquisition and to enhance sensitivity in the m/z range of interest. In this example, each 75 μs scan was comprised of 75,000 data points (a 37.5 μs delay followed by a 37.5 μs digitization event at 2 GHz). For each spectrum, 660 000 scans were co-added. Example data obtained from this analysis is shown in FIG. 2.

While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be clear to one skilled in the art from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the invention. For example, all the techniques and apparatus described above can be used in various combinations. All publications, patents, patent applications, and/or other documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, and/or other document were individually indicated to be incorporated by reference for all purposes. 

We claim:
 1. A sample processing unit, comprising: at least one sample comprising at least one magnetically responsive particle; at least one magnet that generates, or is configured to generate, at least one magnetic field, which magnet is in a substantially fixed position relative to the sample; at least one conveyance mechanism configured to convey the sample between at least first and second positions, wherein at least the first position is within magnetic communication with the magnet when the magnet generates the magnetic field; and, at least one rotational mechanism, which rotational mechanism is configured to rotate the sample when the sample is in at least the second position.
 2. The sample processing unit of claim 1, wherein the magnet comprises a permanent magnet.
 3. The sample processing unit of claim 1, wherein the magnet comprises an electromagnet.
 4. The sample processing unit of claim 1, wherein the conveyance mechanism comprises at least one motor.
 5. The sample processing unit of claim 4, wherein at least one motor comprises a stepper motor.
 6. The sample processing unit of claim 4, wherein at least one motor comprises a brushless direct current motor.
 7. The sample processing unit of claim 1, wherein the conveyance mechanism is configured to rotate the sample between the first and second positions.
 8. The sample processing unit of claim 1, wherein the conveyance mechanism is configured to slide the sample between the first and second positions.
 9. The sample processing unit of claim 1, wherein the rotational mechanism is configured to rotate the sample in at least one oscillating motion.
 10. The sample processing unit of claim 1, comprising at least one mounting bracket that is operably connected to one or more of: the magnet, the conveyance mechanism, or the rotational mechanism.
 11. the sample processing unit of claim 1, comprising a desalting station, a sample wash station, a fluid transfer station, or a mixing station.
 12. The sample processing unit of claim 1, comprising at least one wash reagent.
 13. The sample processing unit of claim 1, comprising at least one elution reagent.
 14. The sample processing unit of claim 1, wherein the magnetically responsive particle comprises an anion exchange resin.
 15. The sample processing unit of claim 14, wherein the magnetically responsive particle comprises at least one biopolymer capture reagent.
 16. The sample processing unit of claim 15, wherein the biopolymer capture reagent comprises at least one anion exchange functional group.
 17. The sample processing unit of claim 16, wherein the anion exchange functional group comprises a pK_(a) value of 9.0 or greater.
 18. The sample processing unit of claim 16, wherein the anion exchange functional group is selected from the group consisting of a primary amine, a second amine, a tertiary amine, a quaternary amine, a polyethyleneimine, a charged aromatic amine, a diethylaminomethyl, and a diethylaminoethyl.
 19. The sample processing unit of claim 1, wherein the sample processing unit comprises a controller comprising a programmed processor, a computer, a digital device, a logic device or an information appliance. 